The present invention relates generally to syringes and, more particularly, to a tool for removing syringe needle shields.
Syringes are known in the art as medical devices utilizable for delivering medicament to a patient. Syringes typically include a barrel component and a plunger component. During injection, the plunger forces the medicament out of a distal end of the barrel, through an elongated needle having an interior bore, out of a tip located at the distal end of the needle and into a patient. The needle tip has a geometry that allows the needle to easily puncture a patient's skin and penetrate tissue or a vein. In order to prevent a needle stick, or damage or contamination of the needle tip, syringe assemblies typically include a syringe needle shield, which is essentially a cover that is placed over the needle to enclose the needle tip. The shield also prevents a needle stick before and after using the syringe.
However, the act of removing a needle shield from a syringe assembly is a significant contributor to accidental needle stick injuries. Using both hands, a user typically pulls apart the needle shield from the syringe assembly. When the needle shield is released from the syringe assembly, the user's body reflexes to compensate for the sudden movement caused by the removal. Both of the user's hands often recoil, directing the exposed needle tip back toward the user's hand that is holding the removed needle shield, sometimes causing the exposed needle tip to inadvertently stick the user. In addition to being painful, the inadvertent needle stick can transmit diseases, such as HIV or Hepatitis, if the needle is contaminated. Previous developments have attempted to address this problem.
U.S. Pat. No. 4,915,225 to Tabor, Jr. et al, describes a counter-top mounted needle shield removal device which has two elongated U-shaped cavities, each of which may receive a needle shield that is capped onto a distal end of a syringe barrel. After the needle shield is inserted into a cavity of the removal device at an acute angle, a compression spring within the removal device pushes a distal end of the needle shield toward a proximal end of the cavity. As the needle shield is pushed by the spring, a proximal end of the needle shield engages a mechanical stop located at the proximal end of the cavity. The spring pressure and the mechanical stop effectively lock the needle shield within the cavity so a user can then pull the syringe barrel away from the needle shield with one hand.
If a needle shield is too long, the cavity can not receive and hold the needle shield. If a needle shield is too short, there is insufficient spring pressure to properly secure the needle shield within the cavity. Requiring a compression spring increases manufacturing difficulty and cost. The device must also be mounted to a wall or counter top, which limits the convenience and operability to a user.
U.S. Pat. No. 5,183,469 to Capaccio discloses a mounted needle shield removal tool having a single cylindrical cavity that receives a needle shield. A needle shield is inserted into a proximal end of the cavity and is twisted to engage internal screw threads at a distal end of the cavity, creating a mechanical lock that anchors the needle shield within the removal device. Once the needle shield is anchored, the user can pull the syringe barrel away from the removal device. If the screw threads within the removal tool cannot engage or do not fully engage the needle shield, the device is rendered inoperable. Hand operation alone is unsuitable because the device must be mounted to a surface, limiting convenience to the user.
U.S. Pat. No. 5,512,049 to Fallas discloses a mounted needle shield removal tool comprising two parallel plates, each having U-shaped arms that extend outwardly in the same direction. A space is provided between the parallel plates for receiving a flange on a needle shield. The top U-shaped plate has an extension, which is secured to a table top. After inserting the flange of the needle shield into the space between the parallel plates, the user pulls on the syringe barrel with one hand. The proximal end of the flange engages a distal end of the top U-shaped plate, preventing the needle shield from moving with the syringe barrel, which separates the syringe barrel from the needle shield. This device can only be used with needle shields that include a suitably sized flange. Hand operation alone is unsuitable because the device must be mounted to a surface, limiting convenience to the user.
U.S. Pat. No. 5,087,249 to Deal discloses a hand operated needle shield removal and attachment device comprising clips that define a C-shaped cavity. The clips surround a portion of a outer wall of a needle shield. A handle on the attachment device extends from the C-shaped cavity toward a proximal end of a syringe barrel. The handle allows the user to attach the needle shield to the device without having to directly grasp the needle shield. However, in order to remove the needle shield, the user must directly pinch the clips, which may expose a user to an inadvertent needle stick during recoil. While the device of Deal can be operated solely by hand, the user is provided with little protection when removing the needle shield from the syringe assembly.
WO 03/051423 discloses a hand operated, needle shield removal tool comprising a cylindrical cavity, a top guard plate, and a bottom base plate. The top guard plate is parallel to the bottom base plate, and both plates are perpendicular to, and centered on, the cylindrical cavity. A syringe with a needle shield is inserted into a proximal end of the cylindrical cavity, and the needle shield is gripped by a plurality of spring-like fingers so that when the syringe is pulled upwardly the needle shield is removed. The arrangement of the guard plate and the cylindrical cavity puts the user's hand immediately adjacent to the proximal end of the cylindrical cavity. With the guard plate having such a small surface area, any reflex during detachment potentially causes the uncovered portion of the user's fingers to be inadvertently stuck by the needle.
Accordingly, there is a continuing need for an improved hand operated needle shield removal tool that overcomes, alleviates, or mitigates one or more of the aforementioned drawbacks and deficiencies of the prior art. The present invention addresses the aforementioned problems by providing a pull ring integrally formed to an attachment cavity that engages and holds a needle shield. The pull ring facilitates the removal of a needle shield for users having reduced manual dexterity while also reducing recoil to minimize the potential for needle sticks.